Variable-capacity compressor control valve

ABSTRACT

Provided is a variable-capacity compressor control valve with a simple configuration that can increase the attraction force of an electromagnetic actuator and thus can reduce the size of the control valve. A sub valve element that is a magnetic body made of the same magnetic material as or a different magnetic material from that of a plunger, which is adapted to move a main valve element in the direction to open or close the valve orifice, is fitted in and fixed to the plunger.

TECHNICAL FIELD

The present invention relates to a variable-capacity compressor controlvalve for use in an automotive air conditioner or the like.

BACKGROUND ART

Conventionally, a variable-capacity swash plate compressor such as theone schematically shown in FIG. 6 has been used as a compressor for anautomotive air conditioner. The variable-capacity swash plate compressor100 includes a rotating shaft 101 that is rotationally driven by anon-vehicle engine, a swash plate 102 that is attached to the rotatingshaft 101, a crank chamber 104 in which the swash plate 102 is disposed,a piston 105 that is reciprocated by the swash plate 102, a dischargechamber 106 for discharging refrigerant compressed by the piston 105, asuction chamber 107 for sucking refrigerant, an in-compressor releasepassage (i.e., a fixed orifice) 108 for releasing the pressure Pc in thecrank chamber 104 to the suction chamber 107, and the like.

Meanwhile, a control valve 1′ used for the aforementionedvariable-capacity compressor receives the discharge pressure Pd from thedischarge chamber 106 of the compressor 100 and is configured to controlthe pressure Pc in the crank chamber 104 by controlling the dischargepressure Pd in accordance with the suction pressure Ps of the compressor100. Such a control valve 1′ has, as the basic configuration, a valvebody that includes a valve chamber with a valve orifice, a Psintroduction port communicating with the suction chamber 107 of thecompressor 100, a Pd introduction port arranged upstream of the valveorifice and communicating with the discharge chamber 106 of thecompressor 100, and a Pc outlet port arranged downstream of the valveorifice and communicating with the crank chamber 104 of the compressor100; a valve element (i.e., a valve stem) for opening or closing thevalve orifice; an electromagnetic actuator with a plunger for moving thevalve element in the direction to open or close the valve orifice (i.e.,in the vertical direction); a pressure-sensitive chamber that receivesthe suction pressure Ps from the compressor 100 via the Ps introductionport; and a pressure-sensitive reaction member that urges the valveelement in the direction to open or close the valve orifice inaccordance with the pressure in the pressure-sensitive chamber. Thevalve element and the valve orifice form a valve unit indicated byreference numeral 11′ in FIG. 6 (for example, see Patent Literature 1below).

In the control valve 1′ with such a configuration, when current isflowed through a solenoid portion including a coil, a stator, anattractor, and the like of the electromagnetic actuator, the plunger isattracted by the attractor, and along with this, the valve element ismoved in the direction to close the valve such that it follows theplunger by the urging force of a valve-closing spring. Meanwhile, thesuction pressure Ps introduced from the compressor 100 via the Psintroduction port is introduced into the pressure-sensitive chamberthrough an inlet/outlet chamber via a gap formed between the plunger anda guide pipe arranged around the outer periphery of the plunger or thelike. Then, the pressure-sensitive reaction member (e.g., a bellowsdevice) is expansively or contractively displaced in accordance with thepressure (i.e., the suction pressure Ps) in the pressure-sensitivechamber (i.e., contracts if the suction pressure Ps is high, and expandsif it is low), and the displacement (i.e., urging force) is thentransmitted to the valve element, whereby the valve element portion ofthe valve element moves up or down with respect to the valve orifice toregulate the valve opening of the valve unit 11′. That is, the valveopening is determined by the force of attracting the plunger with thesolenoid portion, urging force (i.e., expansion or contraction force)that acts with the expansive or contractive displacement of thepressure-sensitive reaction member, and the urging force of a plungerspring (i.e., a valve-opening spring) and the valve-closing spring. Thepressure Pc in the crank chamber 104 (hereinafter also referred to as“crank chamber pressure Pc” or simply referred to as “pressure Pc”) iscontrolled in accordance with the valve opening.

In response to the aforementioned variable-capacity compressor, animproved variable-capacity swash plate compressor, such as the oneschematically shown in FIGS. 7A and 7B, for example, has already beenproposed that is intended to reduce the time required to increase thedischarge capacity at the compressor actuation time, and suppress orreduce a decrease in the operation efficiency of the compressor at thenormal control time.

A control valve 2′ used for such an improved variable-capacity swashplate compressor 200 has a valve element (i.e., a valve stem) includinga main valve element and a sub valve element, and has an in-valverelease passage 16′ in the main valve element. The control valve 2′basically has a valve body that includes a valve chamber with a valveorifice, a Ps inlet/outlet port communicating with a suction chamber 107of the compressor 200, a Pd introduction port arranged upstream of thevalve orifice and communicating with a discharge chamber 106 of thecompressor 200, and a Pc inlet/outlet port arranged downstream of thevalve orifice and communicating with a crank chamber 104 of thecompressor 200; a main valve element for opening or closing the valveorifice; an electromagnetic actuator with a plunger for moving the mainvalve element in the direction to open or close the valve orifice; apressure-sensitive chamber that receives the suction pressure Ps fromthe compressor 200 via the Ps inlet/outlet port; and apressure-sensitive reaction member that urges the main valve element inthe direction to open or close the valve orifice in accordance with thepressure in the pressure-sensitive chamber. Further, the in-valverelease passage 16′ for releasing the pressure Pc in the crank chamber104 to the suction chamber 107 of the compressor 200 via the Psinlet/outlet port is provided in the main valve element, and the subvalve element for opening or closing the in-valve release passage 16′ isalso provided so that when the plunger is continuously moved upward fromthe lowest position by the attraction force of the electromagneticactuator, the sub valve element moves upward together with the plungerwhile closing the in-valve release passage 16′, and the main valveelement is also moved upward so as to follow the sub valve element.Then, after the valve orifice is closed by the main valve element, ifthe plunger is further moved upward, the sub valve element is configuredto open the in-valve release passage 16′. The main valve element and thevalve orifice form a main valve unit indicated by reference numeral 11′in FIGS. 7A and 7B, while the sub valve element and the in-valve releasepassage form a sub valve unit indicated by reference numeral 12′ (forexample, see Patent Literature 2 below).

At the normal control time (Pd→Pc control time) of the control valve 2′with such a configuration, when current is flowed through a solenoidportion including a coil, a stator, an attractor, and the like of theelectromagnetic actuator, the plunger is attracted by the attractor, andalong with this, the sub valve element moves upward integrally with theplunger, and following the movement of the sub valve element, the mainvalve element is moved in the direction to close the valve by the urgingforce of a valve-closing spring. Meanwhile, the suction pressure Psintroduced from the compressor 200 via the Ps inlet/outlet port isintroduced into the pressure-sensitive chamber through an inlet/outletchamber via a horizontal hole in the plunger or the like, and thepressure-sensitive reaction member (e.g., a bellows device) isexpansively or contractively displaced in accordance with the pressure(i.e., the suction pressure Ps) in the pressure-sensitive chamber (i.e.,contracts if the suction pressure Ps is high, and expands if it is low),and the displacement (i.e., urging force) is then transmitted to themain valve element, whereby the main valve element portion of the mainvalve element moves up or down with respect to the valve orifice toregulate the valve opening of the main valve unit 11′. That is, thevalve opening is determined by the force of attracting the plunger withthe solenoid portion, urging force (i.e., expansion or contractionforce) that acts with the expansive or contractive displacement of thepressure-sensitive reaction member, the urging force of a plunger spring(i.e., a valve-opening spring) and the valve-closing spring, and forcethat acts on the main valve element in the valve opening direction andin the valve closing direction. The pressure Pc in the crank chamber 104is controlled in accordance with the valve opening. In such a case, themain valve element is always urged upward by the urging force of thevalve-closing spring, while the sub valve element is always urgeddownward by the urging force of the valve-opening spring. Thus, the subvalve unit 12′ is closed and the in-valve release passage 16′ is blockedin the main valve element. Therefore, there is no possibility that thecrank chamber pressure Pc may be released to the suction chamber 107 viathe in-valve release passage 16′.

In contrast, at the compressor actuation time, current is flowed throughthe solenoid portion so that the plunger is attracted by the attractorand the sub valve element moves upward together with the plunger.Following the upward movement of the sub valve element, the main valveelement is moved in the direction to close the valve by the urging forceof the valve-closing spring, and after the valve orifice is closed bythe main valve element portion of the main valve element, the plunger isfurther moved upward, whereby the sub valve element opens the in-valverelease passage 16′. Then, the crank chamber pressure Pc is released tothe suction chamber 107 via two passages that are an in-compressorrelease passage 108 and the in-valve release passage 16′ (for details,see Patent Literature 2 below and the like).

CITATION LIST Patent Literature

Patent Literature 1: JP 2010-185285 A

Patent Literature 2: JP 2013-130126 A

SUMMARY OF INVENTION Technical Problem

By the way, although various developments aiming at reducing the size ofcontrol valves have been conducted, if the diameter (i.e., the holediameter) of the in-valve release passage in the variable-capacitycompressor control valve 2′ descried in Patent Literature 2 is increasedto secure a certain flow rate to improve the actuation property, theoutside diameter of the sub valve element, which is adapted to open orclose the in-valve release passage, becomes large, and in turn, theinside diameter of the cylindrical plunger externally arranged aroundthe sub valve element also becomes large. Thus, an area (i.e., amagnetic path area) of the upper end portion (i.e., the upper end face)of the plunger that is opposite the attractor inevitably becomes small,which is problematic in that the attraction force of the electromagneticactuator would decrease and thus that the size (in particular, the sizeof the coil portion of the electromagnetic actuator) is difficult toreduce.

The present invention has been made in view of the foregoing, and it isan object of the present invention to provide a variable-capacitycompressor control valve with a simple configuration that can increasethe attraction force of an electromagnetic actuator and thus can reducethe size of the control valve.

Solution to Problem

In order to achieve the aforementioned object, a variable-capacitycompressor control valve in accordance with the present inventionbasically includes a valve body including a valve chamber with a valveorifice, a Ps inlet/outlet port communicating with a suction chamber ofa compressor, a Pd introduction port arranged upstream of the valveorifice and communicating with a discharge chamber of the compressor,and a Pc inlet/outlet port arranged downstream of the valve orifice andcommunicating with a crank chamber of the compressor; a main valveelement adapted to open or close the valve orifice; an electromagneticactuator including a plunger and an attractor, the electromagneticactuator being adapted to move the main valve element in a direction toopen or close the valve orifice; a pressure-sensitive chamber adapted toreceive a suction pressure Ps from the compressor via the Psinlet/outlet port; and a pressure-sensitive reaction member adapted tourge the main valve element in the direction to open or close the valveorifice in accordance with a pressure in the pressure-sensitive chamber.The main valve element includes an in-valve release passage forreleasing a pressure Pc in the crank chamber to the suction chamber ofthe compressor via the Ps inlet/outlet port. A sub valve element adaptedto open or close the in-valve release passage is provided. One or moremagnetic bodies made of the same magnetic material as or a differentmagnetic material from that of the plunger are fitted in and fixed tothe plunger in order to increase the attraction force of theelectromagnetic actuator.

In a preferred aspect, the magnetic body is a cylindrical member.

In further another preferred aspect, the plunger has a cylindricalshape, and the magnetic body is securely inserted in the plunger.

In still another preferred aspect, the magnetic body is press-fitted inand fixed to the plunger.

In yet another preferred aspect, the magnetic body is adapted to be usedas the sub valve element.

In another preferred aspect, a projected area of the lower face of theattractor with respect to the horizontal plane is equal to a projectedarea of the upper faces of the magnetic body and the plunger withrespect to the horizontal plane.

Advantageous Effects of Invention

According to the variable-capacity compressor control valve inaccordance with the present invention, since one or more magnetic bodiesmade of the same magnetic material as or a different magnetic materialfrom that of the plunger are fitted in and fixed to the plunger, amagnetic path area can be secured and the attraction force of anelectromagnetic actuator can be increased. Therefore, a reduction in thesize (in particular, a reduction in the size of the coil portion of theelectromagnetic actuator) can be achieved.

In addition, a projected area (i.e., an area corresponding to a magneticpath area) of the lower face (i.e., a face that is opposite the plunger)of the attractor with respect to the horizontal plane is equal to aprojected area (i.e., an area corresponding to a magnetic path area) ofthe upper faces (i.e., faces that are opposite the attractor) of themagnetic body and the plunger with respect to the horizontal plane. Thiscan also increase the attraction force of the electromagnetic actuatorwithout increasing the body size. Therefore, a further reduction in thesize (in particular, a reduction in the size of the coil portion of theelectromagnetic actuator) can be achieved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a longitudinal sectional view showing an embodiment of thevariable-capacity compressor control valve in accordance with thepresent invention in which the main valve element is in the openposition and the sub valve element is in the closed position (i.e., atthe normal control time).

FIG. 2 is a longitudinal sectional view showing an embodiment of thevariable-capacity compressor control valve in accordance with thepresent invention in which the main valve element is in the closedposition and the sub valve element is in the closed position (i.e., atthe time of transition to compressor actuation).

FIG. 3 is a longitudinal sectional view showing an embodiment of thevariable-capacity compressor control valve in accordance with thepresent invention in which the main valve element is in the closedposition and the sub valve element is in the open position (i.e., at thecompressor actuation time).

FIG. 4A is a front view of a plunger and a sub valve element used for anembodiment of the variable-capacity compressor control valve inaccordance with the present invention.

FIG. 4B is a right-side view of the plunger and the sub valve elementused for an embodiment of the variable-capacity compressor control valvein accordance with the present invention.

FIG. 4C is a top view of FIG. 4B.

FIG. 4D is a bottom view of FIG. 4B.

FIG. 4E is a sectional view in the direction of the arrow U-U in FIG.4B.

FIG. 5 is a sectional view of a modified example of the plunger and thesub valve element shown in FIGS. 4A to 4E, which is similar to FIG. 4E.

FIG. 6 is a view showing the circulation state of a refrigerant pressurebetween a compressor and a control valve of the first conventional art.

FIG. 7A is a view showing the circulation state of a refrigerantpressure between a compressor and a control valve of the secondconventional art, and showing the normal control time.

FIG. 7B is a view showing the circulation state of a refrigerantpressure between a compressor and a control valve of the secondconventional art, and showing the compressor actuation time.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the drawings.

FIGS. 1 to 3 are longitudinal sectional views each showing an embodimentof the variable-capacity compressor control valve in accordance with thepresent invention. Specifically, FIG. 1 is a view in which the mainvalve element is in the open position and the sub valve element is inthe closed position (i.e., at the normal control time), FIG. 2 is a viewin which the main valve element is in the closed position and the subvalve element is in the closed position (i.e., at the time of transitionto compressor actuation), and FIG. 3 is a view in which the main valveelement is in the closed position and the sub valve element is in theopen position (i.e., at the compressor actuation time).

It should be noted that in the present specification, descriptionsindicating the positions or directions, such as upper, lower, top,bottom, left, right, front, and rear, are used for the sake ofconvenience in accordance with the drawings to avoid complexity in thedescription, but such descriptions do not necessarily indicate theactual positions or directions when the control valve of the presentinvention is incorporated into a compressor.

In addition, in each drawing, a gap formed between some members, aclearance between some members, and the like may be depicted larger orsmaller than their actual dimensions to help understand the presentinvention and also for the sake of convenience to create the drawing.

[Configuration of Control Valve]

A control valve 1 in the shown embodiment has a valve body 20 with avalve orifice 22; a valve element 10 with a main valve element 15 foropening or closing the valve orifice 22; an electromagnetic actuator 30for moving the valve element 10 (i.e., the main valve element 15) in thedirection to open or close the valve orifice (i.e., in the verticaldirection); and a bellows device 40 as a pressure-sensitive reactionmember.

The electromagnetic actuator 30 includes a bobbin 38, an energizationcoil 32 wound around the bobbin 38, a stator 33 and an attractor 34arranged on the inner peripheral side of the coil 32, a guide pipe 35whose upper end portion is joined by welding to the outer periphery ofthe lower end portion (i.e., a step portion) of the stator 33 and theattractor 34, a cylindrical plunger 37 having a bottom and arranged suchthat it is vertically slidable on the inner peripheral side of the guidepipe 35 below the attractor 34, a cylindrical housing 60 externallyarranged around the coil 32, a connector head 31 attached to the upperside of the housing 60 with an attachment plate 39 interposedtherebetween, and a holder 29 arranged between the lower end portion ofthe housing 60 and the lower end portion of the guide pipe 35 andadapted to fix them to the upper portion of the valve body 20. In thisexample, the attractor 34 with a cylindrical shape and having aninsertion through-hole 34 a, which has a smaller diameter than theinside diameter of the stator 33, formed in the center (along the axialline O) of the attractor 34 is integrally molded with the innerperiphery of the lower portion of the cylindrical stator 33. Inaddition, an O-ring 31A, which is a sealing member, is attached to theouter periphery of the connector head 31 (or an annular attachmentgroove formed therein). Herein, a portion of the electromagneticactuator 30 including the coil 32, the stator 33, the attractor 34, andthe like and excluding the plunger 37 is referred to as a “solenoidportion 30A.”

A stator 65 with a short columnar shape is securely attached to theupper portion of the stator 33 by press fitting or the like, and apressure-sensitive chamber 45, which receives a suction pressure Ps in acompressor 100, is formed between the stator 65 on the inner peripheralside of the stator 33 and the attractor 34. The pressure-sensitivechamber 45 has arranged therein the bellows device 40 as thepressure-sensitive reaction member that includes bellows 41, adownwardly projecting upper stopper 42, an upwardly recessed lowerstopper 43, and a compression coil spring 44. Further, a stepped,bar-like pushrod 46, which is a thrust transmitting member, is disposedalong the axial line O below the bellows device 40. The pushrod 46includes an upper small-diameter portion 46 d, an intermediate waistportion (i.e., a sliding portion) 46 c, and a lower small-diameterportion 46 b in this order from the top side. The upper small-diameterportion (i.e., an end portion on the side opposite to the sub valveelement 17) 46 d of the pushrod 46 is fitted and inserted in the recessof the lower stopper 43 and thus is supported therein, and theintermediate waist portion 46 c of the pushrod 46 is slidably insertedin the insertion through-hole 34 a of the attractor 34. The lowersmall-diameter portion 46 b of the pushrod 46 is inserted in the recesshole 17 b of the sub valve element 17 with a recessed cross sectiondescribed below, and a lower end portion 46 a of the pushrod 46 isfitted in a fit-insertion hole 17 c formed in the center of the bottomof the recess hole 17 b.

The sub valve element 17 with a recessed cross section and having therecess hole 17 b, which is vertically long and has approximately thesame diameter as that of the insertion through-hole 34 a of theattractor 34, is securely inserted into the plunger 37 by press fittingor the like. The upper end portion of the sub valve element 17 isaligned with the upper end portion of the plunger 37 (that is, the upperend portion of the sub valve element 17 is positioned with respect tothe inner periphery of the upper end portion of the plunger 37), whilethe lower end portion of the sub valve element 17 is fitted into theplunger 37 with a clearance secured between the lower end portion of thesub valve element 17 and the bottom of the plunger 37 (with a clearancethat allows the flanged latch portion 15 k of the main valve element 15to slightly move vertically, which will be described in detail later).The fit-insertion hole 17 c, which is recessed and adapted to havefit-inserted therein the lower end portion 46 a of the pushrod 46 (orthe lower small-diameter portion 46 b thereof), is formed in the centerof the bottom of the recess hole 17 b of the sub valve element 17.

In addition, a plunger spring (i.e., a valve-opening spring) 47, whichis a cylindrical compression coil spring adapted to urge the sub valveelement 17 and the plunger 37 downward (i.e., in the direction to openthe valve), is provided in a compressed state between a step portion(i.e., an annular terrace face facing downward) formed between the uppersmall-diameter portion 46 d and the intermediate waist portion 46 c ofthe pushrod 46, and the bottom of the recess hole 17 b (i.e., a facethereof facing upward around the fit-insertion hole 17 c) of the subvalve element 17 such that the plunger spring 47 is arranged around thelower small-diameter portion 46 b of the pushrod 46. The plunger spring47 allows the sub valve element 17 to move vertically together with theplunger 37 in a state in which the sub valve element 17 is urgeddownward. With the plunger spring 47 (or the compression force thereof),the sub valve element 17 is urged in the direction to close an in-valverelease passage 16 described below, and the bellows device 40 is heldwithin the pressure-sensitive chamber 45 via the pushrod 46.

Further, as is clear from FIGS. 4A to 4E, a central hole 37 b with asmaller diameter than the inside diameter of the plunger 37 is formed inthe center (along the axial line O) of the bottom of the plunger 37, andan insertion hole 37 c with substantially the same diameter as theinside diameter of the plunger 37 (in other words, a larger diameterthan that of the central hole 37 b) is formed in a position eccentricwith respect to the center of the bottom of the plunger 37 such that theinsertion hole 37 c partially overlaps the central hole 37 b. Theinsertion hole 37 c is formed to the depth (i.e., the depth in thevertical direction) to communicate with the internal space of theplunger 37. The diameter of the insertion hole 37 c (i.e., the insidediameter of the plunger 37 and the outside diameter of the sub valveelement 17) is set slightly larger than that of the flanged latchportion 15 k of the main valve element 15 described below, and thediameter of the central hole 37 b is set slightly larger than that ofthe upper small-diameter portion 15 f of the main valve element 15 andslightly smaller than that of the flanged latch portion 15 k, andfurther, the outer peripheral portion of the central hole 37 b on theupper face of the bottom of the plunger 37 is an inner flanged latchportion 37 k to which the flanged latch portion 15 k of the main valveelement 15 is adapted to be latched. The distance (in the verticaldirection) between the bottom (or the upper face thereof) of the plunger37 and the lower end portion (i.e., a planar face) of the sub valveelement 17 is set slightly larger than the height of the flanged latchportion 15 k of the main valve element 15, and the thickness (i.e., theheight in the vertical direction) of the bottom of the plunger 37 is setslightly larger than the height of the upper small-diameter portion 15 fof the main valve element 15 so that the main valve element 15 isvertically movable with respect to the plunger 37 (which will bedescribed in detail later).

In this example, a D-cut surface 37 d is formed in a predeterminedposition on the outer periphery of the plunger 37, and a gap 36 isformed between the outer periphery of the plunger 37 (or the D-cutsurface 37 d thereof) and the guide pipe 35. It should be noted thatinstead of the D-cut surface 37 d, one or more vertical grooves may beformed so that the gap 36 is formed between the outer periphery of theplunger 37 and the guide pipe 35.

The valve element 10 has the stepped, shaft-like main valve element 15and the aforementioned sub valve element 17 arranged side by side in thevertical direction (along the direction of the axial line O).

The main valve element 15 arranged on the lower side is produced from anon-magnetic material and has, sequentially arranged from the bottomside, a main valve element portion 15 a, an intermediate small-diameterportion 15 d, a relatively long fit-inserted portion 15 e, the uppersmall-diameter portion 15 f, and the flanged latch portion 15 k. Arelease through-hole 16A partially forming the in-valve release passage16 is provided in the center of the main valve element 15 such that itpenetrates through the center of the main valve element 15 in thevertical direction. The upper end portion (i.e., an inverted truncatedcone surface portion) of the release through-hole 16A is a sub valveseat portion 23 with/from which a lower end portion (i.e., a sub valveelement portion) 17 a of the sub valve element 17 is moved into contactor away.

The upper small-diameter portion 15 f of the main valve element 15 isloosely fitted in the central hole 37 b, and the flanged latch portion15 k of the main valve element 15 has a larger diameter than that of thecentral hole 37 b (and a smaller diameter than the inside diameter ofthe plunger 37) so that when the plunger 37 is moved upward with respectto the main valve element 15, the flanged latch portion 15 k is latchedto the inner flanged latch portion 37 k that is formed by the outerperipheral portion of the central hole 37 b, and thus, latching isachieved and slippage is prevented.

The sub valve element 17 is, as described above, securely inserted inthe plunger 37 above the main valve element 15. The outside diameter ofthe sub valve element 17 (=the inside diameter of the plunger 37) islarger than the outside diameter of the flanged latch portion 15 k ofthe main valve element 15, and the lower end portion (i.e., a planarface) of the sub valve element 17 is the sub valve element portion 17 athat moves into contact with or away from the sub valve seat portion 23,which is the upper end edge of the release through-hole 16A, so as toopen or close the in-valve release passage 16. Herein, the sub valveseat portion 23 and the sub valve element portion 17 a form a sub valveunit 12.

The sub valve element 17 may be formed using the same magnetic materialas or a different magnetic material from that of the plunger 37 that ismade of a magnetic material. If the sub valve element 17 is formed usinga different magnetic material from that of the plunger 37, that is,using a magnetic material with a different magnetic force, theattraction force property of the electromagnetic actuator 30 can beappropriately adjusted.

Herein, although the sub valve element 17 is a single member (or asingle component), the sub valve element 17 may also be a plurality ofmembers put together.

In order to attach the valve element 10 (i.e., the main valve element 15and the sub valve element 17) and the plunger 37 together, for example,the sub valve element 17 may be fixed to the plunger 37 (in apredetermined position inside the plunger 37) by press fitting or thelike, and the flanged latch portion 15 k and the upper small-diameterportion 15 f of the main valve element 15, which has been attached tothe valve body 20 (or a guide hole 19 therein) in advance, may beinserted into the insertion hole 37 c of the plunger 37 from the bottomside, and then, the main valve element 15 may be moved horizontally withrespect to the plunger 37, and further, the upper small-diameter portion15 f of the main valve element 15 may be inserted into the central hole37 b provided in the center of the bottom of the plunger 37 so that themain valve element 15 (or the flanged latch portion 15 k thereof) isarranged below the sub valve element 17.

Meanwhile, the valve body 20 has a two-split structure that includes abody member 20A having a fit recess hole 20C in the center of the upperportion thereof, and a support member 20B that is securely inserted intothe recess hole 20C by press fitting or the like.

The support member 20B is produced from a material with relatively highhardness, such as stainless steel (SUS), and has a protruding stopperportion 24A for defining the lowest position of the plunger 37, on theupper side of a fit-inserted portion 24 that is fitted and inserted inthe recess hole 20C. The fit-inserted portion 24 has a step formedthereon, and at a position below an upper large-diameter portion 24 a, alower small-diameter portion 24 b, which is longer than the upperlarge-diameter portion 24 a in the vertical direction, is provided, andat the lower end of the lower small-diameter portion 24 b, a flangedabutment portion 24 c, which is adapted to abut a step portion (i.e., aterrace face) between the recess hole 20C of the body member 20A and ahousing hole 18, is provided such that it protrudes outward. Inaddition, the guide hole 19 in which the fit-inserted portion 15 e ofthe main valve element 15 is adapted to be slidably fitted and insertedis formed in the center of the support member 20B such that itpenetrates through the support member 20B in the vertical direction, andthe lower end portion of the guide hole 19 is the valve orifice 22(i.e., the valve seat portion) that is opened or closed by the mainvalve element portion 15 a of the main valve element 15. Herein, themain valve element portion 15 a and the valve orifice 22 form a mainvalve unit 11. Since the support member 20B is produced from a materialwith high hardness, such as stainless steel, as described above, thespecific gravity of the support member 20B is also high.

The body member 20A is produced from a material, such as aluminum,brass, or resin, that has relatively low specific gravity (that is, amaterial with relatively low hardness) as compared to stainless steeland the like. An inlet/outlet chamber 28 for the suction pressure Ps inthe compressor 100 is formed around the outer periphery of the stopperportion 24A, and a plurality of Ps inlet/outlet ports 27 are formed onthe outer peripheral side of the inlet/outlet chamber 28 in a state inwhich the support member 20B (or the fit-inserted portion 24 thereof) isinserted in the recess hole 20C of the body member 20A. The suctionpressure Ps introduced into the inlet/outlet chamber 28 through the Psinlet/outlet ports 27 is introduced into the pressure-sensitive chamber45 via the gap 36 (in this example, a gap formed by the D-cut surface 37d) formed between the outer periphery of the plunger 37 and the guidepipe 35, and the like.

Meanwhile, the recess hole 20C of the body member 20A also has a stepformed thereon, and includes an upper large-diameter hole 20Ca in whichthe upper large-diameter portion 24 a of the support member 20B isfitted and inserted, and a lower small-diameter hole 20Cb in which thelower small-diameter portion 24 b is fitted and inserted. The outerperiphery of the upper large-diameter portion 24 a abuts the innerperiphery of the upper large-diameter hole 20Ca (that is, the upperlarge-diameter portion 24 a is fitted in (i.e., fits snugly inside) theupper large-diameter hole 20Ca), and the support member 20B is securelyinserted in the recess hole 20C of the body member 20A in a posture inwhich a small gap is provided between the outer periphery of the lowersmall-diameter portion 24 b and the inner periphery of the lowersmall-diameter hole 20Cb. In addition, the stepped housing hole 18 forhousing the main valve element portion 15 a of the main valve element 15is provided continuously with the center of the bottom of the lowersmall-diameter hole 20Cb. A valve-closing spring 50, which is a conicalcompression coil spring, is provided in a compressed state between thestep portion provided on the inner periphery of the housing hole 18 anda step portion (i.e., a terrace face) 15 g provided on the outerperiphery of the lower portion of the main valve element portion 15 a ofthe main valve element 15. Thus, with the urging force of thevalve-closing spring 50, the main valve element 15 (or a step portionbetween the fit-inserted portion 15 e and the upper small-diameterportion 15 f thereof) is pressed against the plunger 37 (or the bottomthereof).

The inside of the housing hole 18 (i.e., a portion below the valveorifice 22 of the support member 20B) is the valve chamber 21. Aplurality of Pd introduction ports 25 communicating with a dischargechamber 106 of the compressor 100 are provided in the lowersmall-diameter hole 20Cb of the recess hole 20C, and a ring-like filtermember 25A is arranged around the outer periphery of the Pd introductionports 25. In addition, a plurality of horizontal holes 25 scommunicating with the Pd introduction ports 25 are provided in thelower small-diameter portion 24 b of the fit-inserted portion 24.

In addition, the lower end portion of the body member 20A has a lid-likemember 48, which functions as a filter, fixed thereto by engagement,press fitting, or the like. A Pc inlet/outlet chamber (or inlet/outletport) 26, which communicates with a crank chamber 104 of the compressor100, is provided above the lid-like member 48 and below the housing hole18. The Pc inlet/outlet chamber (or inlet/outlet port) 26 communicateswith the Pd introduction ports 25 via the valve chamber 21→the gapbetween the valve orifice 22 and the main valve element portion 15 a→thegap between the lower portion of the guide hole 19 and the intermediatesmall-diameter portion 15 d→the horizontal holes 25 s of the lowersmall-diameter portion 24 b→the gap between the lower small-diameterportion 24 b and the lower small-diameter hole 20Cb.

In addition, in this embodiment, the release through-hole 16A formed inthe main valve element 15, the central hole 37 b and the insertion hole37 c provided in the plunger 37, the inlet/outlet chamber 28, and thelike form the in-valve release passage 16 for releasing the pressure Pcin the crank chamber 104 to a suction chamber 107 of the compressor 100via the Ps inlet/outlet ports 27. The in-valve release passage 16 isadapted to be opened or closed as the sub valve element portion 17 a ofthe sub valve element 17 is moved into contact with or away from the subvalve seat portion 23 that is the upper end edge of the releasethrough-hole 16A of the main valve element 15.

Herein, in the control valve 1 of this embodiment, when the plunger 37,the main valve element 15, and the sub valve element 17 are at thelowest position (i.e., when the bottom end face of the plunger 37 abutsthe stopper portion 24A, the main valve unit 11 is in the fully openposition, and the sub valve unit 12 is in the fully closed position) asshown in FIG. 1, a clearance in the vertical direction between the mainvalve element portion 15 a of the main valve element 15 and the valveorifice 22 (i.e., the valve seat portion) is represented by a first liftamount Lv, and a clearance between the inner flanged latch portion 37 kof the plunger 37 and the flanged latch portion 15 k of the main valveelement 15 is represented by a predetermined amount La. The maximum liftamount (i.e., a second lift amount) Lp of the plunger 37 (i.e., the liftamount of from the lowest position to the highest position of theplunger 37) corresponds to the first lift amount Lv+the predeterminedamount La.

[Operation of Control Valve]

Next, the operation of the control valve 1 with the aforementionedconfiguration will be schematically described.

At the normal control time (i.e., Pd→Pc control time), the lift amountof the plunger 37 (and the sub valve element 17) is slightly greaterthan the first lift amount Lv at the maximum, and at the compressoractuation time (i.e., Pc→Ps control time), the lift amount of theplunger 37 (and the sub valve element 17) is the second lift amount Lp.

That is, at the normal control time (i.e., Pd→Pc control time), when thesolenoid portion 30A including the coil 32, the stator 33, the attractor34, and the like is supplied with current and thus is energized, theplunger 37 and the sub valve element 17 are both attracted (upward) bythe attractor 34, and following the movement of the plunger 37 and thesub valve element 17, the main valve element 15 is moved upward (i.e.,in the direction to close the valve) by the urging force of thevalve-closing spring 50. Meanwhile, the suction pressure Ps introducedfrom the compressor 100 through the Ps inlet/outlet ports 27 isintroduced into the pressure-sensitive chamber 45 through theinlet/outlet chamber 28 via the gap 36 between the outer periphery ofthe plunger 37 and the guide pipe 35, and the like, and the bellowsdevice 40 (i.e., the inside thereof is at a vacuum pressure) isexpansively or contractively displaced in accordance with the pressure(i.e., the suction pressure Ps) in the pressure-sensitive chamber 45(i.e., contracts if the suction pressure Ps is high, and expands if itis low), and the displacement is then transmitted to the main valveelement 15 via the pushrod 46, the sub valve element 17, and the like,whereby the valve opening (i.e., the clearance between the valve orifice22 and the main valve element portion 15 a) is regulated, and thepressure Pc in the crank chamber 104 is controlled in accordance withthe valve opening. Along with this, the inclination angle of the swashplate 102 and the stroke of the piston 105 in the compressor 100 arecontrolled so as to increase or decrease the discharge capacity.

In this case, the main valve element 15 is always urged upward by theurging force of the valve-closing spring 50, while the sub valve element17 is always urged downward by the urging force of the valve-openingspring 47. Therefore, the sub valve element portion 17 a is in a stateof being pressed against the sub valve seat portion 23 (i.e., the subvalve unit 12 is closed), and the in-valve release passage 16 is blockedin the main valve element 15. Therefore, there is no possibility thatthe crank chamber pressure Pc may be released to the suction chamber 107via the in-valve release passage 16.

In contrast, at the compressor actuation time, the solenoid portion 30Ais supplied with current and thus is energized, and the plunger 37 andthe sub valve element 17 are both attracted (upward) by the attractor34. Following the upward movement of the plunger 37 and the sub valveelement 17, the main valve element 15 is also moved upward, and thevalve orifice 22 is closed by the main valve element portion 15 a of themain valve element 15. Then, the plunger 37 and the sub valve element 17are further moved upward, whereby the sub valve element 17 opens thein-valve release passage 16, and thus, the pressure Pc in the crankchamber 104 is released into the suction chamber 107 via two passagesthat are an in-compressor release passage 108 and the in-valve releasepassage 16.

Specifically, until the upward movement amount of the plunger 37 (andthe sub valve element 17) reaches the first lift amount Lv, the mainvalve element 15 is moved in the direction to close the valve by theurging force of the valve-closing spring 50 such that it follows theupward movement of the plunger 37 and the sub valve element 17. Then,when the upward movement amount reaches the first lift amount Lv, thevalve orifice 22 is closed by the main valve element portion 15 a of themain valve element 15 (i.e., the state shown in FIG. 2), and the plunger37 and the sub valve element 17 are further moved upward by thepredetermined amount La with the main valve unit 11 in the closed valvestate (i.e., the state shown in FIG. 3). In other words, after theupward movement amount of the plunger 37 and the sub valve element 17has reached the first lift amount Lv, the sub valve element 17 isattracted together with the plunger 37 toward the attractor 34 by thepredetermined amount La until the inner flanged latch portion 37 k ofthe plunger 37 is latched to the flanged latch portion 15 k of the mainvalve element 15 (i.e., the first lift amount Lv+the predeterminedamount La=the second lift amount Lp). In such a case, since the mainvalve element 15 remains still in the closed valve state, the sub valveelement portion 17 a of the sub valve element 17 is lifted from the subvalve seat portion 23 by the predetermined amount La, whereby thein-valve release passage 16 is opened. When the inner flanged latchportion 37 k of the plunger 37 is latched to the flanged latch portion15 k of the main valve element 15, neither the plunger 37 nor the subvalve element 17 is lifted any further even if the solenoid portion 30Agenerates an attraction force.

In this embodiment, although the sub valve element 17 is securelyinserted in the plunger 37 in a state in which the upper end portion ofthe sub valve element 17 is aligned with the upper end portion of theplunger 37, it is also possible to change the position of the upper endportion of the sub valve element 17 with respect to the position of theupper end portion of the plunger 37 as shown in FIG. 5, for example, soas to adjust the attraction force property of the electromagneticactuator 30.

As described above, in the variable-capacity compressor control valve 1of this embodiment, the sub valve element 17 (which is a single memberin the example shown in the drawing but may also include a pluralitymembers), which is a magnetic body formed of the same magnetic materialas or a different magnetic material from that of the plunger 37, isfitted in and fixed to the plunger 37. Therefore, a magnetic path areacan be secured and the attraction force of the electromagnetic actuator30 can be increased. Thus, a reduction in the size (in particular, areduction in the size of the coil 32 portion of the electromagneticactuator 30) can be achieved.

Furthermore, a projected area (i.e., an area corresponding to a magneticpath area) of the lower face (i.e., a face that is opposite the plunger37) of the attractor 34 (i.e., a portion other than the insertionthrough-hole 34 a) with respect to the horizontal plane is substantiallyequal to a projected area (i.e., an area corresponding to a magneticpath area) of the upper faces (i.e., faces that are opposite theattractor 34) of the sub valve element 17, which is the magnetic body,and the plunger 37 (specifically, the total face of the upper face ofthe sub valve element 17 and the upper face of the plunger 37) withrespect to the horizontal plane. This can also increase the attractionforce of the electromagnetic actuator 30 without increasing the bodysize. Therefore, a further reduction in the size (in particular, areduction in the size of the coil 32 portion of the electromagneticactuator 30) can be achieved.

REFERENCE SIGNS LIST

-   1 Variable-capacity compressor control valve-   10 Valve element-   11 Main valve unit-   12 Sub valve unit-   15 Main valve element-   15 a Main valve element portion-   15 k Flanged latch portion-   16 In-valve release passage-   17 Sub valve element-   17 a Sub valve element portion-   17 b Recess hole-   17 c Fit-insertion hole-   18 Housing hole-   19 Guide hole-   20 Valve body-   20A Body member-   20B Support member-   20C Recess hole-   21 Valve chamber-   22 Valve orifice-   23 Sub valve seat portion-   24 Fit-inserted portion-   24A Stopper portion-   25 Pd introduction port-   26 Pc inlet/outlet port-   27 Ps inlet/outlet port-   28 Inlet/outlet chamber-   30 Electromagnetic actuator-   30A Solenoid portion-   32 Coil-   33 Stator-   34 Attractor-   34 a Insertion through-hole-   35 Guide pipe-   37 Plunger-   37 b Central hole-   37 c Insertion hole-   37 k Inner flanged latch portion-   40 Bellows device (pressure-sensitive reaction member)-   45 Pressure-sensitive chamber-   46 Pushrod-   46 a Lower end portion of pushrod-   46 b Lower small-diameter portion-   46 c Intermediate waist portion-   46 d Upper small-diameter portion-   47 Plunger spring (compression coil spring)-   50 Valve-closing spring-   Lv First lift amount-   La Predetermined amount-   Lp Second lift amount

1. A variable-capacity compressor control valve comprising: a valve body including a valve chamber with a valve orifice, a Ps inlet/outlet port communicating with a suction chamber of a compressor, a Pd introduction port arranged upstream of the valve orifice and communicating with a discharge chamber of the compressor, and a Pc inlet/outlet port arranged downstream of the valve orifice and communicating with a crank chamber of the compressor; a main valve element adapted to open or close the valve orifice; an electromagnetic actuator including a plunger and an attractor, the electromagnetic actuator being adapted to move the main valve element in a direction to open or close the valve orifice; a pressure-sensitive chamber adapted to receive a suction pressure Ps from the compressor via the Ps inlet/outlet port; and a pressure-sensitive reaction member adapted to urge the main valve element in the direction to open or close the valve orifice in accordance with a pressure in the pressure-sensitive chamber, wherein: the main valve element includes an in-valve release passage for releasing a pressure Pc in the crank chamber to the suction chamber of the compressor via the Ps inlet/outlet port, a sub valve element adapted to open or close the in-valve release passage is provided, the plunger has a cylindrical shape, and one or more magnetic bodies made of the same magnetic material as or a different magnetic material from that of the plunger are securely inserted in the plunger in order to increase an attraction force of the electromagnetic actuator.
 2. The variable-capacity compressor control valve according to claim 1, wherein the magnetic body is a cylindrical member.
 3. (canceled)
 4. The variable-capacity compressor control valve according to claim 1, wherein the magnetic body is press-fitted in and fixed to the plunger.
 5. The variable-capacity compressor control valve according to claim 1, wherein the magnetic body is adapted to be used as the sub valve element.
 6. The variable-capacity compressor control valve according to claim 1, wherein a projected area of a lower face of the attractor with respect to a horizontal plane is equal to a projected area of upper faces of the magnetic body and the plunger with respect to the horizontal plane. 